From owner-freebsd-hackers@FreeBSD.ORG  Wed Jun 27 19:15:13 2012
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From: Marcel Moolenaar <marcel@xcllnt.net>
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Date: Wed, 27 Jun 2012 12:14:57 -0700
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References: <4FE9B01C.30306@yandex.ru> <201206270807.23347.jhb@freebsd.org>
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To: Christian Laursen <xi@borderworlds.dk>
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Cc: Doug Rabson <dfr@freebsd.org>, Marcel Moolenaar <marcel@freebsd.org>,
	Pawel Jakub Dawidek <pjd@freebsd.org>,
	freebsd-current <freebsd-current@freebsd.org>,
	freebsd-hackers <freebsd-hackers@freebsd.org>,
	Andriy Gapon <avg@freebsd.org>, "Andrey V. Elsukov" <bu7cher@yandex.ru>
Subject: Re: [CFC/CFT] large changes in the loader(8) code
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On Jun 27, 2012, at 12:08 PM, Christian Laursen wrote:

> On 06/27/12 16:28, John Baldwin wrote:
>> On Wednesday, June 27, 2012 8:45:45 am Andrey V. Elsukov wrote:
>>=20
>>> When we are in the FreeBSD, our loader can detect that device size
>>> is lower than it see and it will work. When primary header is OK, =
then
>>> other OSes should work with this GPT. When it isn't OK, you just =
can't
>>> load other OS :)
>>=20
>> Ah, yes.  The solution to violating standards is to make sure you =
never
>> use standards-compliant software.  That's a great argument. :)
>>=20
>> (Although not entirely uncommon.  Standards aren't always perfect, =
but if
>> we had a way to not gratuitously violate them it would be nice to =
avoid
>> doing so.)
>=20
> To be standards compliant and allow whole-disk based mirroring to work =
at the same time wouldn't nested GPT work like this?

GPTs don't nest.

> Nothing but FreeBSD would understand the freebsd-geom partition type, =
so the inner GPT device should be valid and standards compliant.

If it were standards compliant, it would be discoverable by non-FreeBSD.
That clearly isn't the case -- hence it's not standards compliant. What
for example if someone wanted to share the swap partition between Linux
and FreeBSD?

--=20
Marcel Moolenaar
marcel@xcllnt.net